Thieds to john l



J. T.` HAWKNS.' .Bnffer Spring for Printing Machines.

No. 237,915. Patented Feb. 22.1881.

Y, UNITED STATES PATENT.y ErrcEo JOHN T. HAWKINs, or TAUNTON, MAssAcHUsETTs, AssIeNoa OE TWO THIHDs To JOHN L. BHOWEH, OF NEW YORK, N. LAND ALEX. E.. BROWN,

OF MONT CLAIR, JEVV` JERSEY.

BUFFER-SPRING FOR PRINTING-MACHINES.

SPECIFICATION forming part of Letters Patent N o. 237,975, dated February 22,1881.

Application filed February 13, 1880.

To all whom it may concern:

Be it known that I, JOHN T. HAWKINs, of Taunton, in the county of Bristol and State of Massachusetts, have invented a new and useful Improvement in Buffer-Sprit] gs for Printing-Presses, which improvement is fully set forth and illustrated iu the following specilication and accompanying drawings, in which- Figures 1 and 2, respectively, illustrate a 1o side elevation, partly in section, and a plan of the lower part of a printing-press, embodying the improvements constituting the invention herein described and claimed.

In a large number of the varieties of printing-presses having reciprocating type-beds it is necessary to counteract or overcome the momentum of the type-bedateach end ofits stroke, and this is generally accomplished by means of springs in some form; but as such presses zo are run at varying speeds it becomes necessary to so adjust these springs, automatically or otherwise, that the reaction afforded by them may be varied )proportionatelyT to said speeds. Where metallic springs are used for this'purz5 pose they generally consist of a series in helical form, which resist the momentum ofthe bed by their compression. With nearly all such springs heretofore `used a variation in theirresistance to comport with varying speeds 3o of the bed has been obtained solely byincreasing the initial tension or compressive set of the springs. Inall these types of presses the distance through which the springs may act upon the bed is limited by the fact that the 3 5 normal motion of the bed while the impression is being taken cannot be interfered with without detriment to the character of the Work. The mechanism, therefore, of such machines is such that the springs are allowed to act upon 4o the bed only through an arbitrary and constant distance, and this being the case the bed always begins to compress the springs at the same time of itstravel for either end. Under the above-mentioned conditions, if the initial compressive set of the springs be increased for the purpose of 'resisting the greater momentum due to an increased speed of bed, the springs must react upon the bed more violently at the commencement of their action than at slower speeds of the bed, and must also accu- 5o mulate greater resistance up to the end ofthe stroke of the bed, equal only to the change made in their initial tension or compressive set. The action and effect, therefore, of such springs at high speeds of bed, when thus arranged, are very different from their action and effect at low speeds of the same, and the higher such speeds the greater must be the departure, Linder such circumstances, from the theoretically perfect action of a spring. 6o The action of such springs, in order tovbe perfect and uniform in overcoming the momentum of any such moving body as the reciprocating bed of a printing-press at any and all of its different speeds, should offer practi-v cally the same initial resistance, constituting a zero of resistance77 at the commencement of the beds motion, accumulating up to the necessary maximum at the end ot' the stroke of the bed, said maximum spring resistance 7o and the ratio of accumulation of such resistance alone varying with the speed of bed.

The object,tl1erefore, of this invention is to so adapt and arrange in a printing-press a series of buffer-springs that their above-mentioned perfect action may be, as nearly as possible, obtained practically, the method employed of adjusting said springsfor varied speeds of the bed of the press effecting no change in their initial reactiveV force or Zero of 8o resistance, whatever that may be, but varying the accumulation of that resistance and its maximum degree for any given speed of bed at pleasure.

The spring mechanismconstituting this invention is provided with a divided index arc or scale, which indicates at sight, without necessitating any trial adjustments, the points of adjustment for.the said mechanism. necessary to` insure its proper reaction in opposition to 9o the momentum of the bed at any desired number of revolutions'of the press or speed ot' its bed-an object of great importance to correctly and quickly discern, not only thereby saving the pressmans time and much wearand tear 9 5 of the machinery, if not actual breakage of parts, but also thereby conducing to easy and less noisy motion of parts and greater precision and excellence of work.

The several parts and their arrangement designed to effect these objects will now be described in connection with the above-mentioned figures of the drawings, and then be specifically set forth in the claims.

In the said figures the invention is shown in two forms of arrangement as applicable to two different styles or varieties of machine. In some printing-presses the type-bed is not supported at the center ot' its width, except immediately under vthe impression-cylinder. In such form of press the arrangement of springs shown on the left half of the iigures is preferable, in order to prevent any tendency of the spring mechanism to spring or depress the centralparts of the bed, the resistance of the spring mechanism other than that in direct line of the travel ofthe bed being, in this case, in a horizontal direction. In th ose printin g-presses in which the type-bed is supported at one or more points near the center of its width the more simple arrangement of springs shown on the right-hand half ofthe figures is used, the resistance ofi'ered by the springs other than that in direct line of motion of the bed being, in this case, vertically downward.

In the drawings the lower part of the frame ofthe press is designated by the letter A, the base-piece by the letter B, and the type-bed by the letter b.

' To the bed b are attached the usual curved shoes S S, which act upon the rollers R It, which latter are pivoted to the free ends of the lever Ll in the vertical arrangement on the right of the gures, and to the upper arm, L, ofthe levers L L in the horizontal arrangement at the left. In the vertical arrangement at the right the lever L' is pivoted at its lower end in the bracket b', attached to the basepiece B. In the horizontal arrangement at the left the lever consists of the two separate arms L L,united to a connecting body or shaft, m, of cylindrical or other suitable form, and is pivoted in the brackets b b', attached to the side frame A. The lower arm, L', of the lever L L in the horizontal and the lever L' in the vertical arrangement contain each a curved slot whose curve corresponds to the arc of a circle struck from the pivotal point I).

The rods r r r each have placed upon them helical springs 7L h h. The central rod, r', is pivoted at one end at the point P to any suitable part of the press, and the block T slides freely upon it. Its other end is secured in the block T by the nut n, the block T sliding freely upon the outer rods, r r. The said outer rods are secured at one end to the block T, and at the other to the yoke y.

The yoke y is secured at any desired point in the curved slot in the lever L' by means of the bolt and nut N, which bolt serves as a pivot upon which the yoke y oscillates.

Each inner rod, r', at each end of the press is provided with a stop, c, in order to limit the inward motion of the block T, which also, under this construction, limits the inward position ot' the lever-arms L on the left and L on. the right, and consequently the position ot' each ot the rollers R It. The inward motion of the levers and their rollers being limited by the contact of the blocks T T, with the stops c c, leaves the levers, when not in action, (the rollers R Rnot being in contact with the shoes S S,) without any tension being exerted upon them bythe springs, and permits of the bolt and nut N, with its attached yoke y, being adjusted in the curved slots of the levers without effort. The initial compression of the springs h l1l may be varied, if desired, by means of the nuts n. A mark or point upon the yoke y, and a divided curved line laid off on the lever-arms L-the divisions on which correspond to the required position of the yoke y or bolt and nut N in the curved slot for the required speeds or number of strokes of bed indicated by numbersserve as a guide tothe printer in adjusting for such speeds.

The curved slots in the lever-arms L L being each an arc of a circle struck from the center of oscillation of the yoke y, the initial compression ofthe springs remains constant, while the farther from the center of oscillation ofthe levers L Ll the yoke y is secured the more rapid will the accumulation of resistance be in the springs, and vice versa, the springs receiving a varying amount of compression for every position of the yoke y.

I do not limit myself to the use ot' levers with curved slots therein, as these levers may be made solid, with different methods of securing the pivot-bolt and nut N and yoke y in different positions upon said levers, said bolt and yoke describing an arc of a circle from the pivotal point I?. All such devices, therefore, which move in arcs of circles upon said levers are within the principle of this my in- `vention.

Having thus fully described my said improvement and its method ot' operation as ot' my invention, I claim,-

l. In combination with the reciprocating bed of a printing -press, a series of buffersprings attached at one end to a pivotal center of oscillation, and at the other end adjustably upon or within an arc or curved slot of a rocking lever, whereby the reaction of said springs is varied proportionately to the speed and momentum of said bed without changing the initial compressive set or tension of said springs, substantially as set forth.

2. ln combination with the reciprocating bed of a printing-press, a set of buffer-springs adjustably connected to a rocking lever and provided with a pivotal rod having thereon a stop, c, as described, whereby the inward motion ot' said lever is limited, while leaving it free from pressure for the purpose of adjustment, substantially as set forth.

IOO

IOS

IIO

3. In combination with the reciprocating bed of a printing-press and buEer-springs, as described7 a rocking lever provided with an adjusting are, whereby7 While the initial com- 5 pressive set or tension of said springs is preserved constant, their reaction is increased or diminished for varying speeds of said bed by their varied adjustment Within or upon said arc, substantially as set forth.

JOHN T. HAWKINS.

Witnesses:

ELIsHA T. J AoKsON, H. T. MONTGOMERY. 

